Dry sprinklers may be used in wet or dry pipe fire protection systems. In a wet-pipe fire protection system, all the system pipes contain water for immediate release through any sprinkler that is activated. In a dry-pipe fire protection system, branch lines and other distribution pipes may contain a dry gas (air or nitrogen) under pressure. Once activated, the dry sprinklers distribute fire-extinguishing fluid, preferably water, in the room or building. Industry accepted standards, such as for example, the National Fire Protection Association (NFPA) standard entitled, “NFPA 13: Standards for the Installation of Sprinkler Systems” (2010 ed.) (“NFPA 13”) defines a dry sprinkler as a “sprinkler secured in an extension nipple that has a seal at the inlet end to prevent water from entering the nipple until the sprinkler operates.” Known dry sprinklers generally include an inlet containing a seal or closure assembly, some length of tubing connected to the inlet, and a fluid deflecting structure located at the other end of the tubing.
The fluid supply for a sprinkler system may include, for example, an underground water main that supplies a vertical riser having a piping distribution network atop the riser with branch lines that carry the pressurized supply fluid to the sprinklers. The inlet of the sprinkler may be secured to a branch line by one of a threaded coupling or a clamp coupling. An exemplary known dry sprinkler is shown and described in U.S. Published Patent Application No. 2007/0187116 to Jackson et al. There exists a need for a single dry sprinkler having multiple alternative coupling arrangements. Moreover, there is a need for the alternative coupling arrangements to be able to connect to standard pipe fittings, i.e., T-fittings, pipe nipples, pipe reducers, etc, that may be encountered in either a wet or dry sprinkler system.